Eagle drill file formats, EXCELLON vs GERBER_RS274X

I sent off a set of pcb files to a pcb fabricator recently, and today I was notified thae were having a problem with the .TXT drill file I had supplied, and could I send them an EXCELLON format file instead?

So I generated the drill files using EXCELLON (produced a .dri file and a .TXT file), and I compared the output to the GERBER_RS274X file.

Now, the board has a grand total of 98 drill holes. The EXCELLON .TXT file was just over 100 lines long, and looked like:

%
M48
M72
T01C0.0320
T02C0.0360
T03C0.0400
T04C0.1300
%
T01
X9800Y2750
X9800Y3750
X9800Y8750
X9800Y9750
X9800Y4750
X9800Y5750
X9800Y7750
X9800Y6750
X9800Y10750

etc.

Fairly easy to grasp the general idea of what's going on, with the X and Y coordinates for each hole taking up one line. Some other info not quite sure what's going, presumably set-up info for drill size, etc. But anyway, nothing very surprising.

OTOH, I got a bit of a shock looking at the GERBER_RS274X .TXT file.

Obviously a different format, with the file starting off like this:

G75*
G70*
%OFA0B0*%
%FSLAX24Y24*%
%IPPOS*%
%LPD*%
%AMOC8*
5,1,8,0,0,1.08239X$1,22.5*
%
%ADD10C,0.0010*%
D10*
X011360Y014680D02*
X011362Y014719D01*
X011368Y014757D01*
X011377Y014795D01*
X011391Y014831D01*
X011407Y014867D01*
X011428Y014900D01*
X011451Y014931D01*

etc., finishing up with:

X018950Y010980D01*
X004300Y007630D02*
X003500Y008430D01*
X003500Y007630D02*
X004300Y008430D01*
M02*

but the file went on for over 3600 lines! To describe drilling 98 holes!

That just sounds nutty to me. What's up? Is my version of Eagle (6.2) producing wacky GERBER_RS274X drill files for some reason?

I'm new to Eagle, and I thought I'd ask the more experienced Eagle users here to compare experiences.

gerber isn't really a drill format; it's a photoplotter format. Looking at the file produced on a random board with a gerber viewer, it looks like what it's doing is drawing the outline of each hole with line segments...

Your board house did a good job spotting this!

Ok, thanks for the insight. Just to be a bit more explicit, in case anyone else comes across the same problem, the board house I'm using is ITEADstudio and the .cam file I'm using to produce the camera-ready files is their "ITEADstudio_CAM for Eagle6.x.cam" file.

I had a look into the .cam file to see if there was any clues there. Interestingly, there is this section:

[Sec_1]
Name[de]="Bohrdaten"
Name[en]="drill data"
Name[zh]="drill data"
Prompt[en]=""
Prompt[zh]=""
Device="EXCELLON"
Wheel=""
Rack=""
Scale=1
Output="%N.TXT"

This suggests that the .cam file should have specified the drill data output in the EXCELLON format automatically; I must have somehow overriden this by explicitly selecting "GERBER_RS274X" in the drop-down list within Eagle before processing the job, perhaps because I had read that this was the format they expected to see the files in. (Well, - almost!)

Actually, I don't recall doing this, but it's the sort of thing I could well imagine doing. I can read instructions and sometimes overthink things, particularly if something is new, and I really want it to be right first go.

Perhaps this will stop someone else making the same mistake.

Anyway, thanks for you advice. The ITEADstudio folks seem pretty easy to work with, so I'm sure we'll get it sorted out.

T01, T02 are tool numbers that are described in the .txt file.

T01C0.0320 Tool 1 .032 " (thru hole size for an .028 plated hole Big Via?
T02C0.0360 Tool 2 .036 " (thru hole size for an .028 plated hole component hole?
T03C0.0400 Tool 3 .040 " (thru hole size for an .035 plated hole .019 header pin?
T04C0.1300 Tool 4 .130 " (thru hole size for an .125 plated hole mounting screw?

T01 Pick tool #1
X9800Y2750 Via @ 9.8 X 2.75 from datum or 0,0 reference (usually lower left most corner [I used a 1" offset from 0,0]
X9800Y3750 3.75 Note a common set of X or Y numbers... This is how the drill machine works... minimum steps per operation make the shortest tool path.
X9800Y8750 ...
Plain and common board data but very strange the first time. I suspect that the other set of erroneous numbers was due to a wrong {slightly} command being issued in Eagle to generate the drill files. However you know now what they 'should' look like, so making that mistake... Should happen once
I've never used Eagle... Yet. I vastly prefer Protel/Altium... I suppose after giving it a little thought... The low end cad (Eagle @ $500 full unlimited and Altium @ $8 or $9000 for a "Full Seat"
Forces the MFR to add all the useful bells and whistles

I always used Gerbers for PCB artwork and Excellon for Drill Files.

Doc

When I order from iteadstudio, I zip up & send them all 13 files that their .cam file generates. Have not had a problem with the numerous orders I've purchased - see all the green boards here as examples. I'm waiting on another order right now even, just sent the files in Saturday afternoon for 2 board types.
http://www.crossroadsfencing.com/BobuinoRev17/